Category Archives: Efficiency

Post navigation

Five years ago I looked at the efficiencies of various electric vehicles and was very impressed with the progress Tesla made with the Model S versus the Roadster. Several months ago, someone commented on my blog that I do the same analysis on the Model 3, but all the data was not yet available (Yes, I could have written this several months ago).

The data I generated in 2012 was a conversion from the MPGe issued by the EPA. In the five years since, drivers are more comfortable thinking in pure electric terms such as Range and kWh (kilowatt-hours) of electricity. So I did not use the EPA numbers at all in the current calculations. The final numbers do differ but not in any significant way for this high level analysis.

The efficiency analysis is quite simple. First, how many miles of range can you go with a given battery pack. So for the new Model 3 long range with 310 miles of range and a 74kWh battery, you can drive 4.19 Miles using 1 kWh. All eight vehicles fall within a range of 2.95 to 4.38 miles per kWh.

To calculate efficiency of a vehicle, you need to also consider the weight of the car. How much mass are you pushing along that one mile. This number is listed in Ton-Miles / kWh. Here again the English measuring system is very strange. We normally think in pounds, and a ton is 2,000 pounds. To calculate the efficiency measure of Ton-Miles / kWh, you simply multiply the weight of the car by the pervious range / energy number.

The “efficiency data” is quite interesting. All the current Tesla vehicles fall within a very narrow range of 7.24 to 8.05 Ton-Miles / kWh.

Some of this data is a little tricky to calculate depending upon exact car options. Tesla also did not report a lower weight for the Model 60, so the numbers are not exact but just give a general idea. Surprisingly, the Model 3 is in the same efficiency range as the S and the X. The Roadster, the BMW i3, Fiat 500e and the Nissan Leaf are much less efficient. Perhaps the easy efficiency improvements were already implemented with the Model S.

Today I drove the car and noticed a significant energy improvement on a regular route. I live in the hills and when I drive down to the flats, I generate some energy and when I drive back up to the house, I use quite a bit of energy. The altitude change is about 300 feet. My car’s average usage is typically about 330 Wh/mile in the local area. My lifetime Wh/mile is a bit lower than that but I’ve been across country in the Model S. The only time I experienced numbers close to 300 Wh/mile was driving on very flat freeways in mild weather.

With the new 7.0 software, rear wheel drive cars now have Torque Sleep. Tesla developed this technology for the dual drive cars. Torque Sleep is the Tesla terminology for turning off a motor when it is not needed. For the dual drive cars with a motor driving each axle, I would suspect there are many times that the car is more efficient with only one motor running. With 7.0, Tesla has now added this technology to the RWD classic cars like mine. Torque sleep on a RWD allows the only motor to go to sleep; effectively the car is in neutral but maintains control.

Getting Great Efficiency with 7.0 Software

Today on my way down to the flats after 7 miles, my Wh/mile usage was noticeable and shockingly low – only about 183 Wh/mile. I decided to return on the exact same route. On the route home as you see on the first half of the screen I got 419 Wh/mile for the 7.1 miles to drive back home. I got an average of 301 Wh/mile on the short 14.2 mile trip.

A couple other owners have report similar improvements, although nothing in the 7.0 release notes indicates any quantitative change. But I’m more than happy to use less energy and have effectively more range on my battery.

On steep downhills, energy can be regenerated by running the motor in reverse. But Tesla must have figured out a sweet spot on a less steep grade where the car can continue at speed but can’t really regenerate energy so the software instead turns the motor off. On my route down, I am assuming there are some shallow downgrades that fit this requirement.

I will continue to watch this data for a longer period of time. Torque sleep on a RWD car may only have a limited set of road conditions to work. It would be entertaining to have an indicator on the dash that the motor is sleeping.

Last week I went from my home in the San Francisco Bay Area to Ashland, Oregon and back in my Tesla with software version 6.2.4.153. I do this trip twice a year as I really enjoy the plays at the Oregon Shakespeare Festival — where 2/3 are not Shakespeare plays — along with the wonderful food and ambiance in the town itself.

On the way up, I drove a circuitous route through the Petaluma supercharger and experimented with the new trip planning feature, and on the way back I explicitly tested the feature. The trip planner technically is still in Beta and was added to help us plan our trips and reduce range anxiety. Unfortunately, the software still has quite a few problems that inadvertently caused me some minor range anxiety.

Tesla divides the software into three different features: trip planner, range assurance, and navigation. The trip planner helps you determine how much time to charge at each supercharger. The range assurance software lets you know that you potentially may be running out of energy while driving. The navigation software has been part of the software since the Model S began shipping. To the end user, all three of these pieces of software have high degrees of interaction. This review of the trip planner software inevitably discusses all the software in totality.

Informal Testing

On the way to Oregon, I stopped in at the newer Petaluma supercharger and decided to drive up through Calistoga and avoid some of the very boring Interstate 5 (I-5) driving. Prior to the trip, I planned the journey in some detail using evtripplanner.com. The total miles between the Petaluma supercharger and the Corning supercharger on I-5 is 165 miles, which should use up 52.6kWh on my 85 with 21” wheels in typical nice California weather.

In Petaluma when I selected the Corning supercharger, the navigation system really wanted me to go to the Vacaville supercharger first. I could not overwrite the path as the software does not allow any waypoints on your drive. Waypoints are intermediate points that you can select to choose between alternative routes. The Tesla navigation system has a very strong preference for freeways. By the time I got to Calistoga, the software finally gave up and routed me directly to the Corning supercharger showing I would have a 28% battery upon arrival.

I went for a very nice hike in Robert Lewis Stevenson State Park which is at the summit of a small mountain range. When I got back, the software was completely confused and reported that it would only have 5% of battery when I got to Corning and that I needed to drive slowly.

Tesla Range Assurance Warning

Since I was paying close attention to this new software and have driven cross country in the Tesla, I was not alarmed and realized my problem was likely that the car could not connect to the internet. After driving downhill about 10 miles, the 3G connection finally kicked in and the number shot back up to about 28% battery remaining.

Software Weakness #2 – The trip planner needs to store more information so that in period without internet access, the software does not report incorrect data.

The next day I headed towards Ashland after charging that morning at the Mt. Shasta supercharger. I was only going to drive to Ashland and stay there and return to the same supercharger. Because I have done this route a few times in the Tesla, I did not pre-plan my trip to and from the Shasta supercharger beforehand. I charged the car at Mt. Shasta to what I suspected was “full enough” and not a range charge; I unfortunately did not note the exact amount of charge.

The driving distance between Mt. Shasta and Ashland is only 75 miles and there are a few slower chargers in town. But I would have dearly loved to have a round trip feature on the trip planner, so I would have known how much I needed to charge in Mt. Shasta. The elevation change is 1,653 feet so using the number of miles is not sufficient to estimate charging needs. I did not remember how much I had charged on previous trips.

Software Weakness #3 – The Trip Planner needs a roundtrip feature.

Ashland

Blink Charger With Almost Unreadable Screen

Ashland has a few chargers in town, so I decided to stop and try to top off the Tesla at one of them. Even if the Tesla software is far from perfect, I do not particularly enjoy dealing with external charging stations. The stations in Ashland are no exception. I have charged there once before. But Ashland is very strict with their parking rules; I have gotten a ticket in the past for staying about 15 minutes past my four hour allowed time in the same parking lot.

I was a little nervous with the ubiquitous signs stating “Head In Parking Only” when the cord would not reach while parking head in. The second problem was that I simply could not read the cracked and dirty screen in the direct sunlight. The third problem was that when I pulled out my Blink charging card, I got the error “Access Denied”. I incorrectly figured I had enough juice and gave up.

Pavement Where Tesla Suspension Needs to be Raised

The hotel I like to stay in Ashland has a terrible entrance to their parking lot. Under the small outbuilding is a eight car parking garage with a short but steep entrance. On the pavement are scratch marks from the many cars that scrape the pavement.

I have earlier raised the car in this exact same location, but I figured the car would automatically raise itself. Unfortunately, the Tesla seemed to have a bad memory and I scraped the car a tiny bit. I manually raised the suspension, and the screen said “Auto-raising location” after the fact. As a test, I drove away, lowered the suspension, and re-entered the parking lot but the car did not want to raise itself automatically.

Software Weakness #4 – The auto-raising location detection or activation does not seem to always take affect where needed.

Tesla Auto Raising Feature Report on the Screen But Not in Reality

The morning when I was leaving Ashland, I selected the Mt. Shasta supercharger on the map, I realized I did not have enough energy to get to Mt. Shasta and the car wanted to go to the next supercharger to the North. I decided to top off at the Blink charger. I backed in and called Blink, who said that particular card was not activated. I must have used the iphone app the other time I used their system. The nice feature about superchargers is that they are significantly less complicated. There are several charging networks with various maps, cards, smartphone apps, cable lengths, charging rates and connector types. With infrequent use of general charging, these relatively easy differences can feel complicated. The superchargers are always free and always have the same cable.

The Real “Test”

List of Upcoming Superchargers and Time Needed at Each Stop

After an unexpected lovely morning charging in Ashland enjoying a late breakfast, I decided to embark on the real test of the Tesla trip planner. I was going to drive straight home and follow the instructions given by the Trip Planner. I was not going to take any significant detours other than a quick stop or two right off the freeway where needed. I decided to do a formal “test” of this new feature.

I was going to visit as many superchargers as needed and charge the exact amount of time listed.

For this journey, the total amount of supercharging would be exactly an hour at three different superchargers: Mt. Shasta (15 minutes), Corning (25 minutes) and Vacaville (20 minutes).

While driving I watched to see if the numbers changed. I kept close to the speed limit perhaps exceeding it by up to 5mph. The test occurred on a Sunday afternoon where I-5 is actually reasonably busy and has a comfortable 70mph speed limit for most of the journey. For late April the weather was a bit warm in the high 80s but not exceptionally hot for the central valley of California.

Supercharger Mt. Shasta

When I arrived at the Mt. Shasta supercharger I was the only Tesla there.

Charging Progress Screen

The software does a nice job reporting progress while charging. It lists how many more minutes you need to charge and also the amount of energy you will have left at the next charging station. The estimates also include a negative charge, which is a nice feature to monitor while waiting.

I quickly filled up as needed in the 15 minutes of time listed. I was comfortable with how many miles I had in the battery. When I am at home, I like to see the amount of energy in the battery listed as a percentage, but when traveling I like to see the distance in rated miles (not ideal), so I can quickly compare it to the amount I would need to travel.

After the 15 minutes were up, the car let me know it was ready to go both on the car’s screen and the Tesla Iphone app.

Driving to Corning

On the way to Corning, I noticed that the software seems to think in 5 minute intervals. From time to time it seemed to estimate that it might take 20 minutes to charge at one of the superchargers, than it changed its mind to 25 minutes. I’m not sure why Tesla decided to not make the number of minutes more granular as they are still estimates.

Corning Supercharger

At Corning there was another Tesla there, but I pulled into a charger that was not paired with theirs. I went for a stroll, but I was not hungry enough to grab a bite to eat and was going to find something in Vacaville.

My charge took the 25 minutes as required, and the car told me “You have enough energy to continue on your trip”. I recorded on the Tesla app a charge of 140 miles. Google maps indicates the driving distance is 113 miles. EV trip planner also says there is a drop of 174 feet. Although the buffer was not large, I was comfortable enough driving on.

Williams

A little after 5pm, the hunger pangs hit in and I decided to find some vegetarian fast food. Just off the exit in Willows, CA is a Burger King, which sells a vegetarian burger. After picking one up, the range assurance software became very unhappy. I had not even added a mile to my trip, but it wanted me to go back to Corning. I refused and checked my battery level and was comfortable I could get to Vacaville. I continued on driving just under the speed limit at 68 or 69 mph and kept my kwH / mile at a reasonable level. I was comfortable with the amount of energy in my battery.

I turned off the navigation as it continued to want me to make a U-turn. I briefly became a bit anxious; I was finding the navigation system was giving me more range anxiety than I have had in the past; I did not actually have “range anxiety” but I was slightly disappointed that I unexpectedly need to pay more attention to my energy usage than expected. In my 40,000 miles of driving the Tesla I have never experienced any true range anxiety. I have experienced a few periods of time where I needed to drive conservatively. These few cases were planned in that I knew I was pushing the limits of charge in my battery before I began driving.

I turned the software on again a few times to see what it decided to do. Somewhere in the middle of the two supercharging stations, it told me to go find another place to charge!

Unexpected Mid Journey Warning too Far Away From Any Chargers

For entertainment purposes, I hit the show chargers option. It wanted me to drive over the mountains and go to some wineries on the way to Calistoga. I was definitely not going to do that option, and turned off navigation and continued my conservative driving with the cruise control on. When I asked the Tesla where to go at one point it wanted me to drive to the Roseville supercharger first and arrive there with zero charge! The distance between the Corning supercharger and the Vacaville supercharger is 113 miles, whereas the distance between the Corning supercharger and the Roseville supercharger is 128 miles.

Navigator Re-routed Me to Roseville

Software Weakness #5 – The software needs to remember in the cache that it had earlier told me I had enough energy to get to the next supercharger. I was driving within the speed limits. Just because I used up perhaps a wee bit more energy and would arrive with 20 miles left instead of 25, the software should not get completely confused.

Ironically just across the street from the Burger King is a Motel 6 with a Sun Country charger. Also fifteen miles before Vacaville is a public charger in Winters, CA. These two options along with a few other choices along I-5 and in Woodland would have been much better choices in a real charging emergency. Charging stations are not ubiquitous along I-5 but do exist.

Software Weakness #6 – When suggesting emergency charging, the software should list all charging stations. Currently it appears to list only Tesla HPWC and superchargers but not the more ubiquitous chargers by other companies. Even better yet, it should tell you to significantly slow down. I could have easily driven 60mph.

As I was approaching Vacaville, I began to speed up a bit. The software finally settled down and routed me to Vacaville with some remaining charge.

Vacaville Supercharger

The Vacaville supercharger was quite busy. I pulled into a non-paired stall with 17 miles left. Another person arrived just before me but selected a paired stall. I have noticed that many Tesla owners simply drive up to any supercharger stall without even checking the stall designation. Perhaps they are uninformed that their charge can be greatly reduced if they pick a paired stall with another recent arrival.

Backing up is a bit tricky in some of the stalls in Vacaville. There room in front of the middle stalls is hampered by perpendicular parking in front. By the time I backed in, the out of state drivers had already walked away from their charging stall.

Continuing my test, I charged until the the time the car told me I had enough energy to complete my journey home, which was exactly 20 minutes. At this point every charger was full. As I was simply going home and my test theoretically complete, I pulled out to give my stall to the newcomer. But taking a second look while parked in front of the 8 Teslas charging, I saw the following statistics:

Driving distance to home – 104 miles

Rated range charge – 111 miles

Expected charge upon arrival 5%

Software Weakness #7 – The warning indicator “You have enough energy to continue on this trip” is not carefully programmed. The software told me I had enough energy to continue on the trip with a very small margin below 25 miles. I am guessing that the timer stuck to the initial 20 minutes instead of charging time instead of accurately measuring the charge level upon completion.

Instead of continuing, I saw another car had left and backed into and charged some more. The charge rate was painfully slow as I was in a paired stall with I suspect someone pulling a lot of energy. I probably left about 10 minutes later knowing I had to drive conservatively to make it home. The Bay Area has a lot of gentle hills and I would need to use a little more energy for the last leg of my trip.

Tire Pressure Warning

About 30 miles away from home, I got the Tire Pressure Warning (TPWS) light come on. I have not received this warning in over a year. In the past I got a lot of false warnings and some very genuine warnings before a potential blow out. I pulled over and looked at the tires and they did not look visibly low. When I got back in the car the warning went away, only to reappear and disappear again 15 miles later after looking at the tires again.

The next day I took the car to my local garage and one tire was lower by about 10 psi and had a nail in it. The TPWS worked well and saved my tire. I’m not sure why the behavior flickered on and off. The perpendicular angle of the nail resulted in a slow leak and the tire is now repaired.

Conclusions

Tesla is headed in the right direction by helping drivers plan their energy usage. They correctly labeled this software as a Beta version. Most of the problems I found were more software weaknesses / enhancements than explicit bugs. Unfortunately in the current condition the software will do little to reduce range anxiety and in some cases may significantly increase range anxiety.

In the current software, Tesla is trying to appease two opposing needs at the same time: range anxiety and optimal charging time. Unfortunately, these two needs are actually inversely correlated. If I want to have no range anxiety, I would fill up the battery as much as possible before continuing or at least add more of a cushion, but that would take up more time at the superchargers. If I want to optimize my charging time, I need to watch the driving speed and monitor the energy usage. If I always keep the battery as low as possible, I could easily have some range anxiety or a trip where I need to monitor energy usage.

Software Weakness #8 – The software should have an option for selecting between truly optimal supercharging times or range anxiety cushions. Clearly the software is aiming that you arrive at the next supercharger with 25 miles left. I find this a reasonable cushion for point to point conservative driving. Perhaps the software should have an option: range or time. The time would be in the current configuration. I doubt anyone would want to plan with less than a 25 mile buffer. The range option would perhaps increase this buffer by 25 miles to 50 miles.

The current software is useful for existing Model S owners, but in its current state it will not address the concerns of the non-tech savvy person who may have range anxiety. I have forwarded this review to Tesla management, and I am confident that the software will improve over time.

For Model S drivers when using this software, I would point out the following five facts before embarking on a road trip:

The amount of time to charge at each supercharger is relatively aggressive leaving you only 25 miles extra driving distance at the speed limit.

You may get some scary warnings if you veer off the software’s designated path.

The Tesla software does not include any non-Tesla chargers – either commercial stations or free if you are close to running out of juice. Please consult other websites or smartphone apps if you are running out of energy.

The software may notify that your battery is full enough to leave the supercharger but may actually need more time. Double check the charge before unplugging.

The software may give you false warnings when out of cell signal range.

Tonight at 8:18pm, Tesla announced the D version of the Model S. The D as many owners guessed stands for Dual motor or an all wheel drive version of the Model S.

An AWD version can really help sales in cold weather climates but also provides significant benefits over 2WD versions

1. Faster acceleration

Elon stated that the 0 to 60 will be 3.2 seconds with the P version of the AWD. This number is really fast and even faster than my Roadster. I have not been excited about the P85 because the acceleration was not nearly as smooth as the Roadster. I hope to get a service loaner P85D in the future to check out the characteristics of this acceleration with two motors not just one.

2. Top speed is higher.

This feature will probably be hard to take advantage of in most places outside of perhaps the German autobahn or very remote locations.

3. Efficiency increases.

ICE cars become less efficient when you add AWD. With the sophisticated electronics, the Tesla D is more efficient than a standard Tesla even with the increased weight of the second motor on the front axel!

The Dual Motor option for the S85 is $4,000 with no listed 0-60 performance increase. The P85D is another $14,600 over the P85. The P85D requires 21″ wheels, the tech package and smart air suspension. The difference between a similarly configured S85 to a P85D is $26,600. In a way I am glad this option was not available when I bought my car as that speed is very tempting.

Auto-pilot Announcement

Along with announcing the D, Elon announced some auto-pilot features that are in the cars that are currently produced. He made it clear that these cars are not autonomous self driving cars. The technology includes

Forward looking radar that can see through fog, snow and sand.

Cameras that with image recognition that can distinguish pedestrians and can read signs.

360 degree ultrasonic sonar that creates a protect cocoon around the car and is sensitive enough to see a small child or a dog.

With these features, the car can self park and automatically brake. On private property, you can summon the car to you.

Although I am more excited about the speed of the D for roller coaster thrills, the auto pilot features are potentially more interesting for many buyers.

This week I had another first in the Tesla world, my first sighting of a Model S with a roof rack in the East Bay.

The Whispbar roof rack system from Yakima is available directly through Tesla for $519. Or you can buy direct through Yakima for the same price. The first price listed is only $449 but does not include the $70 flush kit.

Thule also sells a roof rack with a Tesla adaptor for $454.85 with the following three parts: the podium, the rack and the fit kit. To mount any roof rack on the Telsa, you need to have bought the panoramic roof.

While carrying anything on the roof of a vehicle, electric or ICE, you will be impacting your mileage due to aerodynamics and resistance. Perhaps with an electric vehicle, owners will be more sensitive to any drop in range with a roof rack.

Various owners have reported different Wh/mile performance differences with their roof racks and carriers. These data points are always very difficult to be accurate as weather conditions and speed make a significant difference. The following data has been reported by a few owners: a little over 1% with just the roof rack installed or with snowboards, 10-25% loss with a bicycle, and 10% with a cargo carrier.

I have driven to the mountains many times with skis on the roof. I have also owned a paddleboard for a few years now. The paddleboard is very large and has a measurable impact on my Highlander’s MPG in high speeds or windy conditions. I would assume a similar Wh/mile drop if I put the paddle board on the Tesla.

Since I already own a rack system on my Toyota Highlander, I am in no rush to install one on my Model S. I also feel that I need to at least occasionally drive the Highlander. If I purchase a roof rack for the Tesla, I would also be strongly inclined to buy the Thule rack. Thule makes an excellent paddleboard system, and offered excellent customer support when I accidentally threw away an important part of the system.

I have blogged about the Tesla service several times over the years. I have found the service personnel very courteous and have given them in general high reviews as do other owners, who do not have a visible presence in the internet world.

My car went in again for service recently and I drove a 85 loaner with 19” wheels, coil suspension, parking sensors and a parcel shelf.

Ding on Loaner Vehicle

What was interesting about my recent service experience is that for the first time they are checking both vehicles for door dings and paint issues. The valet said that some customers have complained about the clear coat leaving marks from rain spots. This year has been so dry, outside of some freak summer rain in the early hours, I haven’t thought about rain. The loaner with about 500 miles on it actually had a significant ding on the front of the car.

Car Needs Service

Unfortunately during my service, my loaner vehicle had a failure on the last day. With the new firmware 5.12 on the loaner, I got a generic warning “Car Needs Service”. The car was still completely drivable but the main screen was not responsive to touch and could not be rebooted.

Used Only 314 kWh/mile While Driving the Loaner

A number of smart buyers are buying these loaner vehicles in order to get faster delivery and a slightly less expensive car. I think buying a loaner from Tesla is a good option. Surprisingly when I had this loaner, I drove it at only 314 Wh/mi, which is the lowest value I have ever driven since hypermiling in Utah. In these 125 miles, I did only 20 miles of freeway driving and most of the miles were on boring and busy city streets. Since the loaners are almost the identical car that one already owns, there is no reason to go on a joy ride.

Parcel Shelf

I did notice the slight difference of the coil suspension and the 19” wheels but still found the loaner configuration a very nice option for someone who wants to save money in both the purchase and the tire wear. This loaner was the first car with a parcel shelf, which I liked more than expected. It was unobtrusive and easily hides things in the trunk — even if all you are hiding is reusable grocery bags.

Today I was very excited that they extended the warranty on the 85kWh model S for the drive unit to 8 years and infinite miles. A number of owners had experienced issues with the drive units including another blogger, Dan Edmunds. Many of these issues were relatively minor such as noise during acceleration. Since the drive unit is sealed, the entire drive unit is replaced. Today, Elon Musk made this warranty announcement including that it is retroactive for all Model S 85kWh vehicles!

A couple of new superchargers were added in Utah recently allowing me to drive home along Interstate 70 and Interstate 15 through Utah and Nevada (including a tiny section of Arizona) instead of the long loop back through Gallup New Mexico. At this point of the long journey, I was happy to cut both miles and time.

However, one glaring hole existed for charging. Between Beaver, Utah and Las Vegas, Nevada was a total of 223 miles between superchargers. The weather was also quite warm and the freeway speeds quite high.

EVtripplanner.com lists the journey requiring 268 rated range miles in 82 degree weather. In between Beaver, Utah and Las Vegas, Nevada were very few charging stations. A Nissan dealer in St. George, Utah allows Teslas to charge there but the charge rate is slow. A few RV parks exist along I15, but after calling one I was dismayed to hear it was not possible because they were all booked up for the holiday weekend.

I decided to drive straight to Las Vegas without stopping or charging. Even if the report listed a requirement of about 270 miles needed, I also noticed a large drop in elevation of -3884 feet, which should enable me to not use very much energy.

I decided to hypermile my way to Las Vegas. Hypermiling in an electric vehicle can include many techniques but the following are the ones I used:

Drive significantly slower than the 75 and 80 mph hour speed limits. I decided that I felt safe enough about 20 mph slower than the speed limit if there was plenty of visibility from the rear.

Allow the car to slow down up any small uphills and regain speed on the downhills.

Keep the air conditioner off as much as possible.

Keep the fan off and crack open a window to cool the car.

Enjoy all the other Model S electronics because they run off the 12 Volt battery.

Do not stop and take a break.

Accelerate slowly.

Use the cruise control to maintain a consistent speed.

Other techniques include:

Drafting semi trucks. I dislike people tailgating me and also did not want a lot of road debris hitting the car, so I decided to not try to save energy by drafting trucks.

Putting the car in neutral and coasting. I had earlier played with this on some remote roads but I preferred regenerating energy on the downhills instead of coasting. In some states driving the car in neutral is illegal.

I fortunately had met a couple the day before doing the same trip in their Model S with 19” tires, and texted them to make sure they were successful. They made it to Las Vegas with plenty to spare. My exact data for the journey is listed in the table below. I made it to Las Vegas with 74 miles of rated range in the battery.

When needing to save energy, I prefer to drive conservatively in the beginning and then relax the driving in the second half. Once I hit St. George, Utah I had only 118 miles left to go and 194 rated range listed. I pretty much followed the speed limit from that point on and had the A/C on also. The huge drop in elevation between Cedar City and St. George allowed me to drive between those two cities using only 7.6 kWh.

If I were to drive this route again, I would feel quite comfortable increasing the speed in Utah.